#10 generate Laplacian matrix

open
nobody
None
5
2006-05-25
2006-05-25
Charles Fry
No

While I realize that this can be calculated by
combining other obtainable matrices, it would be nice
if GraphMatrixOperations had methods for generating
Laplacian matrices.

I'd be glad to help with this, too.

Charles

Discussion

  • Joshua O'Madadhain

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    Not sure what you mean by a Laplacian matrix in this
    context. Please provide a reference to a definition.

    (Also, if CERN Colt already does this--I haven't checked--
    it may or may not be useful for us to duplicate this
    capability, since you can convert a Colt matrix into a
    JUNG graph.)

    Joshua

     
  • Joshua O'Madadhain

    Logged In: YES
    user_id=709417

    Not sure what you mean by a Laplacian matrix in this
    context. Please provide a reference to a definition.

    (Also, if CERN Colt already does this--I haven't checked--
    it may or may not be useful for us to duplicate this
    capability, since you can convert a Colt matrix into a
    JUNG graph.)

    Joshua

     
  • Charles Fry

    Charles Fry - 2006-06-27

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    A reference definition can be found at:

    http://en.wikipedia.org/wiki/Laplacian_matrix

    It doesn't look like Colt provides this either.

    Charles

     
  • Joshua O'Madadhain

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    Charles:

    Thanks for the reference. I've never actually seen that
    definition before; what is this useful for?

    Feel free to donate an implementation of these methods
    (which ought to be pretty trivial) by emailing the source
    code to the support forum; if you do, we'll try to
    incorporate it when we have time.

    Joshua

     
  • Charles Fry

    Charles Fry - 2006-06-29

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    The Laplacian matrix is useful for performing spectral
    analysis of the graph, as outlined in the book Spectral
    Graph Theory (and elsewhere). Personally, I calculate the
    eigenvalues of the Laplacian matrix in order to measure
    expansion.

    Submitted code to the list (sorry about going about it in
    the wrong way).

    Charles

     

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No, thanks